Bottom Line:
All formulas were least accurate when eyes were with axial length of >33 mm, and median absolute errors were significantly higher for those eyes than eyes with axial length = 26.01-30.00 mm.Conclusions.And for axial length over 33 mm, the Haigis formula could be more accurate.

ABSTRACTPurpose. This study aims to compare the accuracy of intraocular lens power calculation formulas in eyes with long axial lengths from Chinese patients subjected to cataract surgery. Methods. A total of 148 eyes with an axial length of >26 mm from 148 patients who underwent phacoemulsification with intraocular lens implantation were included. The Haigis, Hoffer Q, Holladay 1, and SRK/T formulas were used to calculate the refractive power of the intraocular lenses and the postoperative estimated power. Results. Overall, the Haigis formula achieved the lowest level of median absolute error 1.025 D (P < 0.01 for Haigis versus each of the other formulas), followed by SRK/T formula (1.040 D). All formulas were least accurate when eyes were with axial length of >33 mm, and median absolute errors were significantly higher for those eyes than eyes with axial length = 26.01-30.00 mm. Absolute error was correlated with axial length for the SRK/T (r = 0.212, P = 0.010) and Hoffer Q (r = 0.223, P = 0.007) formulas. For axial lengths > 33 mm, eyes exhibited a postoperative hyperopic refractive error. Conclusions. The Haigis and SRK/T formulas may be more suitable for calculating intraocular lens power for eyes with axial lengths ranging from 26 to 33 mm. And for axial length over 33 mm, the Haigis formula could be more accurate.

Mentions:
For the main outcome of MedAE, the Haigis formula achieved the lowest error of 1.025 D (95% confidence interval = 1.297–1.816 D; P < 0.01 for Haigis versus each of the other formulas, Table 2 and Figure 1). In addition, for eyes with absolute errors within 0.5 D of the target, all formulas performed similarly (around 20%), whereas 49.32% and 47.97% of eyes were within 1.0 D of the target using the Haigis and SRK/T formula—42% ~ 52% more than the Hoffer Q formula (33.78%) and Holladay 1 formula (32.43%) (P = 0.007 and 0.003 for Haigis versus Hoffer Q and Holladay 1, resp.). These results were essentially consistent across all endpoints for 2.0-D and 3.0-D postoperative refractive thresholds (Table 3).

Mentions:
For the main outcome of MedAE, the Haigis formula achieved the lowest error of 1.025 D (95% confidence interval = 1.297–1.816 D; P < 0.01 for Haigis versus each of the other formulas, Table 2 and Figure 1). In addition, for eyes with absolute errors within 0.5 D of the target, all formulas performed similarly (around 20%), whereas 49.32% and 47.97% of eyes were within 1.0 D of the target using the Haigis and SRK/T formula—42% ~ 52% more than the Hoffer Q formula (33.78%) and Holladay 1 formula (32.43%) (P = 0.007 and 0.003 for Haigis versus Hoffer Q and Holladay 1, resp.). These results were essentially consistent across all endpoints for 2.0-D and 3.0-D postoperative refractive thresholds (Table 3).

Bottom Line:
All formulas were least accurate when eyes were with axial length of >33 mm, and median absolute errors were significantly higher for those eyes than eyes with axial length = 26.01-30.00 mm.Conclusions.And for axial length over 33 mm, the Haigis formula could be more accurate.

ABSTRACTPurpose. This study aims to compare the accuracy of intraocular lens power calculation formulas in eyes with long axial lengths from Chinese patients subjected to cataract surgery. Methods. A total of 148 eyes with an axial length of >26 mm from 148 patients who underwent phacoemulsification with intraocular lens implantation were included. The Haigis, Hoffer Q, Holladay 1, and SRK/T formulas were used to calculate the refractive power of the intraocular lenses and the postoperative estimated power. Results. Overall, the Haigis formula achieved the lowest level of median absolute error 1.025 D (P < 0.01 for Haigis versus each of the other formulas), followed by SRK/T formula (1.040 D). All formulas were least accurate when eyes were with axial length of >33 mm, and median absolute errors were significantly higher for those eyes than eyes with axial length = 26.01-30.00 mm. Absolute error was correlated with axial length for the SRK/T (r = 0.212, P = 0.010) and Hoffer Q (r = 0.223, P = 0.007) formulas. For axial lengths > 33 mm, eyes exhibited a postoperative hyperopic refractive error. Conclusions. The Haigis and SRK/T formulas may be more suitable for calculating intraocular lens power for eyes with axial lengths ranging from 26 to 33 mm. And for axial length over 33 mm, the Haigis formula could be more accurate.